1. Field of the Inventive Concepts
The inventive concepts disclosed and claimed herein relate generally to shutters, and more particularly, but not by way of limitation, to a shutter assembly for protecting a sensitive light detector such as a photomultiplier tube against harmful exposure to light.
2. Brief Description of Related Art
Analytical instrumentation utilizing luminescence detection is heavily utilized in the pharmaceutical and medical industries. Analytical measurements are often performed using a beam of catalyzing radiation to interact with a specific sample-reagent combination. The resulting photon emission, often very weak, is then detected and measured with a sensitive detector, converted to an electrical signal, and further correlated to provide the actual analytical result.
For example, U.S. Pat. No. 5,709,994 discloses a highly sensitive method of assaying known as a Luminescent Oxygen Channeling Immunoassay (LOCI). The method uses a photosensitizer that generates singlet oxygen upon irradiation, and a chemiluminescent compound that is activated by the singlet oxygen. The photosensitizer and chemiluminescent compound are irradiated with light of a certain wavelength, after which the resulting light emitted by chemiluminescent compound is measured and correlated to provide the assay.
The instrumentation utilized for luminescence-based assays is often physically large due, in part, to the intricate and sensitive optics used. The analyses often involve exposure of the sample to a high intensity light near the field of view of a sensitive detector such as a photomultiplier tube. To protect the sensitive detector, it is common to widely separate the detector from the high intensity light source and to provide path barriers and shutters between the two.
Size is not a major concern in large laboratories facilitating high-throughput screening; however, it would be useful to have a lighter, portable unit or handheld device capable of producing accurate luminescence-based analyses for non-laboratory settings, such as, medical clinics, physicians offices and homes. Compact designs that reduce the optical path can also increase the risk of harmful exposure of the sensitive detector to the high intensity light source.
In view of the foregoing, there is an increasing need for a shutter design that is compact, energy-efficient, and suitable for protecting sensitive detectors in a portable luminescence-based sample analyzer. It is to such a shutter design that the presently disclosed and claimed inventive concept(s) is directed.